A. Field of the Invention
The present invention relates generally to web browsing and, more particularly, to techniques for reducing latency experienced by a user when browsing the world wide web.
B. Description of Related Art
The World Wide Web (“web”) contains a vast amount of information. Information on the web is often presented in the form of web pages formatted as Hypertext Markup Language (HTML) documents. HTML documents may include markup symbols or codes that describe how a web browser should handle rendering of the HTML document. The markup symbols may, for example, indicate the font or style with which a particular section of text is to be displayed, the size and location of an image that is to be displayed, and the location on the web of a link to another web page.
A given web page may include references (“links”) to other web pages or images. The links may refer to information stored at physically distant computing devices that are referred to by a logical address called a domain name. A domain name (also called a host name when associated with a web host) is an alpha-numeric name that is used to locate an organization or other entity on the Internet. A domain name is a meaningful and easy-to-remember “handle” for an Internet address. For example, the domain name “www.google.com” locates an Internet address for “google.com” at Internet Protocol (IP) address 216.239.53.99. An IP address is a number, such as a 32-bit number, that identifies each sender or receiver of information sent across the Internet. Before any communication can be performed with a domain name, the IP address associated with the domain name must be determined.
The domain name system (DNS) defines how Internet domain names are located and translated into IP addresses. Because maintaining a central list of domain name/IP address correspondences would be impractical, under DNS, the lists of domain names and IP addresses are distributed throughout the Internet in a hierarchy of authority.
Accordingly, before a web page stored at a specified domain name can be accessed, the accessing device must first perform (or have previously performed) a DNS lookup operation to find the IP address corresponding to the domain name. DNS lookups can account for significant perceived latency when browsing the Internet. To enhance the Internet browsing experience, it is thus desirable to reduce latency caused by DNS lookups as much as possible.